Coccinia grandis stem fiber polymer composite: thermal and mechanical analysis

Searching for lightweight, economic, bio-degradable, recyclable and eco-friendly material with high specific strength and high specific modulus to reinforce polymer composites finds a viable and potential solution in natural fiber. In the present work, zero cost plentifully accessible Coccinia grandis stem fiber (CGSF) with high cellulose content, specific mechanical properties and salient surface features to ensure good bonding with the polymer matrix is comprehensively characterized for its physical, chemical, thermal, mechanical, surface roughness and microstructural properties. Initially, CGSF is qualified and used as a reinforcement in the fabrication of composite with polyester resin (CGSFC). The critical length of fiber and the best percentage addition of fiber reinforcement were determined based on mechanical testing, which were found to be 40 mm and 40% (wt), respectively. Mechanical properties increased with amount of fiber up to 40% (wt), where fiber pullout, debonding and matrix failure occurred systematically to provide maximum load transfer capability to the composite. Thermal analysis of the fiber confirmed its thermal stability till 250 °C, which is sufficient for any polymeric material. Tensile strength of about 50 MPa, better flexural strength, sufficient energy absorption capacity and hardness affirm the CGSF composite as an alternative structural material for various engineering applications.